Pennsylvania County Atlases and Maps from the 1850s-1870sFrom the Pennsylvania Historical and Museum Commission. Links to Pennsylvania county maps dating from the 1850s through the 1870s. The maps on this page were specifically chosen because they depict a plethora of surface and subterranean features, such as businesses, churches, mineral deposits, mountains, roads, rivers, and schools. More importantly, they also show property owners and dwellings, allowing researchers to place individuals or families in a certain spot at a specific point in time.